Apparatus and method for making frozen confections

ABSTRACT

An apparatus for making a frozen confection product from a liquid food substance comprises a gas port for selectively injecting gas from a pressurized source into the liquid food substance at an injection point to form a mixture, a freeze tube having an inlet end and an outlet end and having a substantially cylindrical wall for containing the mixture therein, a cooling circuit for cooling an external surface of the cylindrical wall, and a whipping auger disposed within the freeze tube for emulsifying the liquid food substance portion of the mixture with the gas portion thereof, the whipping auger propelling a first portion of the mixture in a helical pattern from the inlet end of the freeze tube toward the outlet end and for simultaneously propelling a second portion of the mixture in a direction from the outlet end toward the inlet end of the freeze tube. A method for making a frozen confection from a liquid food substance comprises the steps of mixing a gas with the liquid food substance, introducing the mixture into a freeze tube having an inlet end and an outlet end, propelling a first portion of the mixture from the inlet end of the freeze tube toward the outlet end thereof and sumultaneously propelling a second portion of the mixture from the outlet end of the freeze tube toward the inlet end thereof to emulsify the gas with the liquid food substance, and cooling the mixture.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an apparatus and method for makingfrozen confections. Although suitable for all types or frozenconfections, the apparatus is described in connection with soft-servesorbets and yogurts, for which it has particular advantages.

2. Description of the Related Art

Typical related art commercial frozen confection machines contain fourintegrated systems; an insulated compartment for storing liquid foodsubstances; a gas circuit for providing an edible gas for mixture withthe liquid food substances; a production unit for making a frozenconfection from the mixture of liquid and gas; and a refrigerationcircuit for cooling both the insulated compartment and the productionunit.

The storage compartment is typically connected to the production unit bya tube which defines a food path. In order to minimize bacterialcontamination within the system, it is desirable to minimize the lengthof the food path and the number of components through which the liquidfood substance must pass before it is frozen in the production unit.

The gas circuit is provided to mix gas with the liquid food substancewhich typically serves two functions. First, it inflates the liquid foodsubstance to increase the volume of frozen end product that can beproduced from a given volume of liquid food substance. Second, itdecreases the density of the frozen end product which leads to asmoother texture in the frozen end product.

The production unit, which may be cooled by freon circulated by therefrigeration circuit, typically contains a cylindrical tube forreceiving liquid food substance therein. Augers disposed within the tubechurn the liquid food substance to mix it with the gas and to expose themixture to the cooled walls of the cylinder, thereby freezing themixture.

As the liquid food substance cools in the production unit, its abilityto absorb and be become emulsified with the gas decreases. Thus, if acritical temperature is reached before the gas and liquid are fullyemulsified, pockets of gas will form within the cylinder. When adispensing valve on the cylinder is opened, these pockets of gas may"blow-out", spewing food product through the valve. In addition, productquality may be poor if full emulsification has not occurred.

In order to prevent blow-outs and to provide a fully emulsified product,tho cooling rate may be decreased. However, the slower the mixturecools, the larger the crystal size in the end product. Since smallercrystal size results in a smoother textured end product, a fast coolingrate is desirable.

Some related art devices separately inject the liquid and gas into theproduction unit, and some include premixing units or saturators in thefood path for mixing the liquid and gas before it enters the cooledenvironment of the production unit. A drawback of premixing units isthat they provide additional nooks and crannies within the food paththat may trap food particles and thereby lead to bacterial growth.

Thus, a major drawback of related art devices is their inability torapidly cool a liquid and gas mixture to achieve small crystalstructure, while at the same time ensuring that the gas and liquidbecome fully emulsified.

While related art devices may use pumps to convey liquid food substanceinto a production unit, they may not be designed to always maintain apositive pressure in the system during use. Rather, they may fluctuatebetween positive pressure and atmospheric pressure, or may substantiallyoperate at atmospheric pressure. If the pressure in the system falls toatmospheric pressure, contaminants may enter the system leading tobacterial growth. Thus, more frequent cleaning may be necessary tomaintain a bacteria free environment.

Further, many related art devices are open system devices wherein liquidfood product is poured into an opened holding reservoir or is otherwiseexposed to air from the surrounding atmosphere. Such structure not onlyincreases the possibility that bacteria and foreign particles willcontaminate the food product, but also allows odors in the surroundingatmosphere to be absorbed into the food product, degrading the taste ofthe end product. Hospitals and other institutions that use odoroussanitizing chemicals avoid frozen confection machines in theircafeterias for this very reason.

An object of the present invention is to provide a frozen confectionapparatus and method that rapidly cools a liquid and gas mixture toensure small crystal size.

Another object of the present invention is to provide an apparatus andmethod that ensures full emulsification of the liquid food substance andthe gas even when rapid cooling occurs in the production unit.

A further object of the present invention is to provide an apparatus andmethod for premixing the liquid and the gas while at the same timeminimizing locations within the food path where food particle may becomelodged.

An additional object of the present invention is to provide an apparatusand method that ensures homogeneous mixing of liquid food substance andgas and prevents the occurrence of blowouts.

In addition, it is an object of the present invention to provide afrozen confection apparatus and method that maintains a positivepressure within its food path to discourage the entry of contaminants.

An even further object of the present invention is to provide a frozenconfection apparatus and method that is an hermetically sealed closedsystem in order to prevent either contaminants to enter the system orodors from the surrounding atmosphere to be absorbed into the foodproduct.

Additional objects and advantages of the invention will be set forth inpart in the description which follows and in part will be obvious fromthe description may be learned by practice of the invention. The objectsand advantages of the invention will be realized and attained by meansof the elements and combinations particularly pointed out in theappended claims.

SUMMARY OF THE INVENTION

To achieve the objects and in accordance with the purposes of theinvention, as embodied and broadly described herein, the apparatus formaking a frozen confection product from a liquid food substance,comprises means for selectively injecting gas from a pressurized sourceinto the liquid food substance to form a mixture, tube means having aninlet end and an outlet end and having a substantially cylindrical wallfor containing the mixture therein, means for cooling an externalsurface of the cylindrical wall, and whipping means disposed within thetube means for emulsifying the liquid food substance portion thereofwith the gas portion thereof, the whipping means for propelling a firstportion of the mixture from said inlet end of said tube means towardsaid outlet end in a helical pattern, and for propelling a secondportion of the mixture in a direction from said outlet end toward saidinlet end.

The method of the present invention for making a frozen confection froma liquid food substance, comprises the steps of mixing a gas with theliquid food substance, introducing a mixture of the gas and the liquidfood product into a freeze tube, propelling a first portion of themixture from the inlet end of the freeze tube toward the outlet endthereof and simultaneously propelling a second portion of the liquid ina direction from the outlet end of the freeze tube toward the inlet endthereof to emulsify the gas with the liquid food substance, and coolingthe mixture.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary only and are notrestrictive of the invention, as claimed.

The accompanying drawings which are incorporated in and constitute apart of this specification illustrate one embodiment of the inventionand together with the description serve to explain the principles of theinvention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view in perspective of a frozen confection machineincorporating the present invention;

FIG. 2 is a block diagram depicting the interconnection of keycomponents of the frozen confection machine in accordance with thepresent invention and as shown in FIG. 1;

FIG. 2a is a block diagram depicting an alternative embodiment of theinterconnection of a portion of the components depicted in FIG. 2;

FIG. 3 is a longitudinal view of the freeze tube assembly depicted inFIG. 2;

FIG. 4 is a cross-sectional view taken along line IV--IV in FIG. 3;

FIG. 5 is an end view of the freeze tube assembly as seen from the Adirection in FIG. 3;

FIG. 6 is a longitudinal perspective view of an auger in accordance withthe present invention;

FIG. 7 is an inlet end view of the auger as shown in FIG. 6;

FIG. 8 is an outlet end view of the auger as shown in FIG. 6; and

FIG. 9 is an oblique view of a portion of the auger shown in FIG. 6.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference will now be made in detail to the present preferredembodiments of the invention, examples of which are illustrated in theaccompanying drawings.

As depicted in FIG. 1, frozen confection machine 10 includesrefrigeration/gas storage unit 12, insulated food compartment 14, andproduction unit 16.

As depicted in FIG. 2, freeze tube assembly 32 of production unit 16 isconnected via food line 22 to source of liquid food substance 21 storedin insulated food compartment 14. Preferably, refrigerated food source21 includes a 21/2 gallon bag of liquid food substance connected to foodline 22 with a connector that forms an air-tight seal. Preferably, theliquid food substances contains edible stabilizers that lower thefreezing point of the liquid to below 10° F. Numerous commercial gradestabilizers are available that reduce the freezing point of foodproducts to below 10° F.

A pressurized source of gas 18 (preferably nitrous oxide) is stored inunit 12 and is connected via gas line 20 to food line 22. Refrigerationcircuit 56 is also disposed in unit 12 and is connected viarefrigeration lines 58 and 60 to freeze tube assembly 32 and insulatedcompartment 14.

In accordance with the invention, there is provided an apparatus formaking a frozen confection product from a liquid food substancecomprising means for selectively injecting a gas from a pressurizedsource into the liquid food substance to form a mixture.

As embodied herein, means for selectively injecting gas from apressurized source into the liquid food substance includes gas line 20connected to food line 22 at injection point 24. Injection point 24 mayinclude T-connector 25 disposed in food line 22 for connecting gas line20 to food line 22 at substantially a 9020 angle. The 90° injection ofgas produces turbulence in food line 22 which aids in mixing the liquidand gas.

According to an alternative embodiment of the present invention and asdepicted in FIG. 2a, gas line 20 may be connected directly into a portin pump 30. In this manner, the pumping turbulence caused by pump 30aids in premixing the liquid and gas.

Mixing portion 23 of food line 22 connects T-connector 25 to freeze tubeassembly 32. As liquid and gas travel together through mixing portion 23of food line 22, premixing occurs. Preferably, the length of mixingportion 23 should be sufficient to allow at least 25-30% of the injectedgas to be absorbed into the liquid food substance before the mixtureenters freeze tube assembly 32. In order to achieve 25-30% premixing themixing portion 23 should be at least about 5 or 6 inches in length.Obviously, this minimum length may vary depending upon the ingredientsof the food substance, the gas used, and whether the gas is injectedthrough pump 30 as shown in FIG. 2a.

Preferably, injection point 24 is spaced a predetermined distance fromfreeze tube assembly 32 to allow mixing of liquid food substance and gasto occur before the mixture enters freeze tube assembly 32.

Injection means may also include solenoid valve 26 disposed in gas line20 upstream of T-connector 25 and alligator valve 27 disposed in gasline 20 proximate T-connector 25. Current sensing relay circuit 28electrically connects valve 26 to pump 30 disposed in food line 22downstream of injection point 24. When pump 30 draws a preselectedcurrent such as 3 amps, for example, relay circuit 28 opens valve 26 toinject gas from pressurized gas source 18 into food line 22 at injectionpoint 24. This arrangement prevents freeze tube "blow out" by insuringthat an amount of liquid food substance sufficient to absorb a portionof the injected gas is present at injection point 24 when gas firstenters food line 22. Alligator valve 27 may be provided as a check valveto insure that food substance does not back into gas line 20.

In accordance with the invention, there is also provided tube meanshaving an inlet end and an outlet end and having a substantiallycylindrical wall for containing the mixture therein. As embodied hereinand as depicted in FIGS. 3-5, tube means includes stainless steel freezetube 34, a component of freeze tube assembly 32. Stainless steel freezetube 34 has a delron block 38 affixed at the inlet end thereof. Port 36is disposed in delron block 38 for connection to food line 22. Thus,when pump 30 is activated and valve 26 is opened by relay circuit 28, amixture of gas and liquid food substance is conveyed into freeze tube 34through port 36.

Plate 40 is disposed on the outlet end opening of freeze tube 34opposite delron block 38. Dispensing port 42 is disposed in plate 40 forpermitting frozen end product to exit freeze tube 34. Elongated bolts 46extend from plate 40 for securing dispensing valve assembly 44 (shown inFIG. 1) thereto. Dispensing valve assembly 44 allows frozen end productto be selectively dispensed from cylindrical tube 34.

In accordance with the invention, there is provided means for cooling anexternal surface of the cylindrical wall. As embodied herein and asdepicted in FIG. 4, cooling means includes cooling wall 48 disposedabout freeze tube 34 and spaced a predetermined distance therefrom todefine space 50 therebetween. Inlet port 52 and outlet port 54 aredisposed in cooling wall 48 and are connected to refrigeration circuit56 via lines 58 and 60, respectively.

Refrigeration circuit 56 may include a standard refrigeration circuit 56including a compressor. An air cooled condensing section having a 1.5 hpmotor and rated at 7800 btu's has proven to be effective. The desiredlevel of cooling depends upon the ingredients of the liquid foodsubstance. However, with most frozen sorbets and yogurts, it isdesirable to cool the mixture to between 10° F. and 0° F., preferablyabout 9° F.

It is also desirable to provide in-line devices to protect refrigerationcircuit 56 from damage. A standard strainer 64 is provided in line 58,and a standard filter dryer 64 is provided in line 60 to preventmoisture and foreign particles from damaging the compressor ofrefrigeration circuit 56.

Refrigeration circuit 56 circulates a liquid coolant such as freonthrough space 50 between cylindrical tube 34 and cooling wall 48.Preferably directing means are disposed in space 50 to evenly expose theexterior wall of cylindrical tube 34 to refrigerant. In a preferredembodiment, directing means includes metal rod 62 coiled about tube 34.It is preferable for metal rod 62 to have a diameter substantially equalto the distance between the freeze tube 34 and cooling wall 48. Thus,refrigerant entering inlet port 52 is directed in a spiral pattern aboutthe exterior of cylindrical tube 34, evenly exposing the entire surfaceof freeze tube 34 to refrigerant. In order to further increase coolingefficiency, a well known insulation such as Armaflex™ is wrapped aroundcooling wall 48.

The above described arrangement allows freeze tube assembly 32 to coolmixtures at an accelerated rate thereby inhibiting crystal growth andproviding an end product with a smooth texture. Cooling rates areselectively variable depending upon the product being produced. In orderto selectively vary the cooling rate of freeze tube assembly 32,expansion valves (not shown) may be provided on lines 58 and 60proximate inlet port 52 and outlet port 54, respectively. The expansionvalves include sensors for constantly metering the line temperatures andpressures to open and close the valves when preselected set points arereached. In this manner, the temperature within freeze tube assembly 32may be precisely controlled. When the mixture enters freeze tubeassembly 32 it is at a temperature of approximately 35°-42° F. Freezetube assembly 32 cooperates with refrigeration circuit 56 to cool themixture to about 9° F. in 7-8 minutes or less.

Refrigeration circuit 56 also cools insulated food compartment 14.Refrigerating the liquid food substance serves two important purposes.First, refrigerating the food substance retards spoilage. Second, sincethe liquid food substance entering freeze tube assembly 32 is alreadyprecooled in insulated food compartment 14, the desired high speedfreezing within freeze tube assembly 32 occurs more rapidly.

Bypass valve 68 is provided between lines 58 and 60 for allowing thecompressor of refrigeration circuit 56 to circulate refrigerant whenexpansion valves (not shown) at the freeze tube and insulated foodcompartment 14 are closed. Bypass 68 thereby prevents burn out of thecompressor.

In accordance with the invention, there is provided whipping meansdisposed within the tube means for emulsifying the liquid food substanceportion of the mixture with the gas portion thereof, the whipping meanspropelling a first portion of the mixture in a first direction from theinlet end of the tube means toward the outlet end and for simultaneouslypropelling a second portion of the mixture in a direction from theoutlet end toward the inlet end of said tube means. As embodied hereinand as depicted in FIGS. 6-9, whipping means includes auger 70 havingshaft 72 with a plurality of fins 74 extending therefrom. Auger 70 isrotatably disposed in freeze tube 34 to emulsify the gas and the liquidfood substance and to convey the mixture from inlet end 104 to outletend 106 of freeze tube assembly 34 through rotation of shaft 72.Simultaneously, a pressure differential across each fin 74 causes asecond portion of the liquid to be drawn through openings 76 in fins 74in a direction from outlet end 106 towards inlet end 104 of cylindricaltube 34.

Auger 70 includes whipping fin portion 92 disposed between scooper finportion 90 and dispensing fin portion 94. Whipping fin portion 92includes ten whipping fins 74 uniformly spaced axially along shaft 72.Whipping fins 74 are positioned such that the axial location of theleading edge of each fin 74 corresponds to the axial location of atrailing edge of an adjacent fin 74. Each of fins 74 are welded to shaft72 at an angle φ of 30° relative to central axis 96 of shaft 72. Inaddition, the center line 98 of each of fins 74 is radially spaced fromeach of the other whipping fins 74 by an angle θ of 120°.

Elongated scooper fin 80 is disposed at scooper fin portion 90 of shaft72 and extends toward delron block 38. The center line of scooper fin 80is radially offset from the center line of an adjacent whipping fin 74by 120°. During rotation of shaft 72, scooper fin 80 draws stagnatingmixture away from delron block 38 and insures that gas pockets do notform toward the inlet end 104 of freeze tube 34.

Three dispensing fins 100 are disposed on the dispensing fin portion 94of auger 70. Similar to fins 74, dispensing fins 100 are radially spacedfrom each other by angles of 120°. However, unlike fins 74, the centerlines 102 of dispensing fins 100, lie in the same plane perpendicular tocentral axis 96 of shaft 72. The radial position of center lines 102 ofdispensing fins 100 are offset from center lines 98 of fins 74 by anangle α of 60°.

Each of fins 74 and 100 are perforated with circular openings 76disposed at central portions thereof. The surface area of each opening76 is roughly equal to one quarter of the surface area of each fin 74.As shaft 72 rotates, the rotation in combination with the shape andangling of fins 74 causes low pressure to occur on the forward sides offins 74, and high pressure to occur on the rear sides. Thus, as a firstportion of the mixture is propelled forward in a helical pattern towardsoutlet end 106 by the rotation of fins 74, the pressure differentialacross the fins causes a second portion of the mixture proximate each offin 74 to be drawn rearward toward inlet end 104 through openings 76.The pressure differential also cause a turbulent vortex effect to occuron the rear sides of fins 74 which rapidly emulsifies the liquid and gasportions of the mixture.

Shaft 72 is connected to a motor (not shown) through drive shaft 78 thatextends through a lip seal (not shown) in delron block 38. The lip sealincludes a sleeve that engages drive shaft 78, permitting rotationwithout allowing mixture to escape from freeze tube 34 through the shaftopening. The Varilip™ seal manufactured by American Varaseal™ providesan effective lip seal for drive shaft 78.

The invention may also include pressure means for maintaining a positivepressure on said mixture within said tube means. As embodied herein,pressure means includes pump 30 disposed in food line 22. Preferably,pump 30 is sized to maintain a system pressure of at least 30 psi,preferably 35 psi. It is also preferable for pump 30 to be controlled toexert less force at injection point 24 then the force exerted bypressurized gas source 18. Should the pressure in food line 22 exceedthe pressure in gas line 20, liquid food product may become deposited ingas line 20 leading to bacterial growth. As described earlier, a checkvalve such as alligator valve 27 may be disposed in gas line 20 adjacentinjection point 24 to prevent contamination of gas line 20.

Maintaining a positive pressure in the system serves three importantfunctions. First, the outward force exerted by pump 30 discourages entryof contaminants into the system. This feature in combination with otherfeatures of the invention allow the frozen confection machine to be usedfor extended periods of time between cleanings without the threat ofbacterial contamination.

Second, the pressure environment aids in the homogenous mixing of gasand liquid food substance which is critical to the quality of the endproduct.

Finally, since substances tend to cool faster at elevated pressures,pressure in freeze tube 34 causes the mixture to cool more quickly thenit would otherwise cool at atmospheric pressure. The faster coolingprocess retards crystal growth in the frozen end product leading to asmoother texture.

The present invention has been designed as a hermetically sealed closedsystem. Food line 22 is directly connected to a 21/2 gallon bag ofliquid food substance using a connector that forms an air-tight seal.The entire food path upstream of pump 30 is maintained at a positivepressure to insure that contaminants from the outside atmosphere cannotenter the system. It is also preferable to locate pump 30 eitheradjacent to or within refrigeration unit 14 so that the portion of foodline 22 connecting the source of liquid food substance 21 and pump 30 isrefrigerated to inhibit bacterial growth.

In addition, the invention may be constructed to meet clean-in-place(CIP) standards. In order to meet CIP standards, the food path isconstructed so that there are no "hard 90°" turns wherein particles offood may become lodged. As described earlier, the pressure in food line22 is controlled to be maintained below the pressure in gas line 20 sothat food substance will not back-up into gas line 20. In addition, theuse of the lip seal for drive shaft 78 provides a rotational connectionfree of nooks and crannies that might otherwise trap food particles.

The invention is operable in a cleaning mode wherein a cleaning solutionsource is substituted for the bag of liquid food substance. Duringcleaning, a catch basin is positioned beneath dispensing valve assembly44 to collect spent cleaning solution.

In accordance with the present invention, there is provided a method formaking a frozen confection from liquid food substance comprising thestep of mixing a gas with the liquid food substance. As describedearlier, a gas such as nitrous oxide is injected at a 90° angle intofood line 22. The gas and liquid then travel together into cylindricaltube 34 through mixing portion 23 of food line 22. The turbulence causedby the 90° injection in combination with the travel through mixingportion 23 serves to premix the liquid and gas. In addition, thetemperature in premixing portion 23 is higher than in tube 34. Since gasis absorbed by the liquid more rapidly at higher temperatures, thepremixing line is advantageous for this additional reason. Duringpremixing, approximately 25%-30% of the injected gas is absorbed by theliquid food substance in premixing portion 23 of food line 22.

Valve 26 may be adjusted so that a desired volumetric ratio of gas toliquid food substance may be achieved. It is preferable to adjust valve26 so that the ratio of gas to liquid food substance is at least about1:1. Successful tests have also been achieved at levels as high as about1.4:1.

A high gas inflation ratio serves two important purposes. First, itgreatly increases the amount of end product that can be produced from agiven volume of liquid food substance. Second, it lowers the density ofthe end product to provide a smoother texture.

Also, in accordance with the invention, the method comprises the step ofintroducing the mixture of the gas and the liquid food substance into afreeze tube assembly. As described earlier, mixing portion 23 of foodline 22 conducts the mixture into freeze tube assembly 32 through port36. Freeze tube assembly 32 serves as an evaporator to rapidly cool themixture of liquid food substance and gas.

The method of the present invention also includes propelling a firstportion of the mixture from the inlet end of the freeze tube toward theoutlet end thereof and simultaneously propelling a second portion of theliquid in a direction from the outlet end of the freeze tube toward theinlet end thereof to emulsify the gas with the liquid food substance. Asembodied herein, and as described earlier, whipping is achieved throughthe rotation of auger 70. Whipping should occur vigorously enough sothat molecules of gas surround each liquid molecule.

Preferably, in order to achieve the necessary whipping, the motor thatrotates auger 70 through drive shaft 78 should be capable of maintainingover about 45 rpms. At this rate, auger 70 simultaneously propels themixture in opposite directions within freeze tube 34. As auger 70rotates a majority of the mixture is propelled towards outlet end 106 ina helical pattern. However, a second portion of the mixture is drawntowards inlet end 104 through openings 76 in fins 74. A turbulent vortexoccurs on the inlet end side of each fin 74 which aids in whipping themixture. Of course, the necessary revolutions per minute will varydepending upon the ingredients of the food substance, the type of gasused, and the design of the auger.

The inventors have found that many different liquid food substancesmixed with nitrous oxide require that full emulsification occur beforethe mixture reaches about 12° F.-15° F. Below 15° F., many foodsubstances loose their ability to absorb nitrous oxide. With the augerdescribed above, a rotational speed of 45 rpms is usually sufficient toachieve full emulsification before the critical temperature of 12°F.-15° F. is reached.

The method of the present invention also comprises the step of coolingthe mixture. As discussed earlier, the mixture is cooled in freeze tubeassembly 32. The desired rapid rate of cooling is achieved by exposingsubstantially the entire external surface of freeze tube 34 torefrigerant and pressurizing freeze tube 34 with pump 30.

Other embodiments of the present invention will be apparent to thoseskilled in the art from consideration of the specification and practiceof the invention disclosed herein. It is intended that the specificationand examples be considered as exemplary only with a true scope andspirit of the invention being indicated by the following claims.

What is claimed is:
 1. An apparatus for making a frozen confectionproduct from a liquid food substance, the apparatus comprising:means forselectively injecting gas from a pressurized source into the liquid foodsubstance at an injection point to form a mixture; tube means having aninlet end and an outlet end and having a substantially cylindrical wallfor containing said mixture therein; means for cooling an externalsurface of said cylindrical wall; and whipping means disposed withinsaid tube means for emulsifying the liquid food substance portion of themixture with the gas portion thereof, said whipping means propelling afirst portion of said mixture into a helical pattern from said inlet endof said tube means toward said outlet end and having a plurality ofportions spaced from one another within said tube means forsimultaneously propelling a second portion of said mixture in adirection from said outlet end toward said inlet end of said tube means.2. An apparatus according to claim 1, further comprising a conduit forconnecting a source of liquid food substance with said tube means, saidconduit having a mixing portion extending from said injection point tosaid tube means, said means for injecting including a gas inlet portdisposed at said injection point.
 3. An apparatus according to claim 1,wherein said cooling means includes a cooling wall disposed about saidcylindrical wall a predetermined distance therefrom to define a spacetherebetween, said cooling wall including a refrigerant inlet port and arefrigerant outlet port disposed therein.
 4. An apparatus according toclaim 3, further including means for directing fluid refrigerant in saidspace between said refrigerant inlet port and said refrigerant outletport to substantially evenly expose said cylindrical wall torefrigerant.
 5. An apparatus according to claim 4, wherein saiddirecting means includes a metal rod coiled about said cylindrical wallfor directing refrigerant in a spiral pattern about said cylindricalwall between said refrigerant inlet port and said refrigerant outletport.
 6. An apparatus according to claim 3 wherein said cooling meansfurther includes a refrigeration circuit connected to said refrigerantinlet and said refrigerant outlet ports, said cooling circuit includinga compressor disposed therein.
 7. An apparatus according to claim 1further including pressure means for maintaining a positive pressure onsaid mixture within said tube means.
 8. An apparatus according to claim7, wherein said pressure means includes a pump disposed in-line withsaid conduit.
 9. An apparatus according to claim 8, wherein said pump issized to maintain a minimum of 30 psi in said tube means.
 10. Anapparatus according to claim 1, wherein said whipping means includes anelongated shaft rotatably disposed along a central axis of said tubemeans, said shaft having a plurality of fins extending therefrom.
 11. Anapparatus according to claim 10, wherein at least a portion of said finsinclude a perforation disposed therein.
 12. An apparatus according toclaim 11, wherein said perforations in said fins include openingsdisposed at a central portions thereof.
 13. An apparatus according toclaim 12, wherein a surface area of each of said openings isapproximately equal to one quarter of a surface area of a correspondingfin.
 14. An apparatus according to claim 10, wherein said shaft includesa dispensing fin portion proximate said outlet end of said tube meansupon which a plurality of dispensing fins are disposed, a scooping finportion disposed proximate said inlet end of said tube means having ascooping fin extending therefrom, and a whipping fin portion disposedbetween said dispensing fin portion and said scooping fin portion, andhaving a plurality of whipping fins disposed thereon.
 15. An apparatusaccording to claim 14, wherein said whipping fins are angled at about30° with respect to said central axis.
 16. An apparatus for makingfrozen confection from a liquid food substance stored in a reservoir,the apparatus comprising:a freeze tube having an inlet end and an outletend; a T-connector having a first port, a second port, and a third port,said first port being connected to the reservoir via a food line; amixing conduit having a predetermined length for connecting said secondport of said T-connector to said freeze tube, said third port of saidT-connector being disposed at an angle of about 90° with respect to saidsecond port and being connected to a pressurized source of gas; coolingmeans for cooling said freeze tube; and whipping means disposed withinsaid freeze tube for emulsifying the liquid food substance portion ofthe mixture with the gas portion thereof, said whipping means propellinga first portion of said mixture in a helical pattern from said inlet endof said freeze tube toward said outlet end and having a plurality ofportions spaced from one another within said freeze tube forsimultaneously propelling a second portion of said mixture in adirection from said outlet end toward said inlet end of said freezetube.
 17. A method for making a frozen confection from a liquid foodsubstance, the method comprising the steps of:mixing a gas with theliquid food substance to form a mixture; introducing the mixture into afreeze tube having an inlet end and an outlet end; whipping the mixtureby propelling a first portion of the mixture from the inlet end of thefreeze tube toward the outlet end thereof while simultaneouslypropelling a second portion of the mixture, from a plurality of spacedapart areas within the freeze tube, in a direction from the outlet endof the freeze tube toward the inlet end thereof to emulsify the gas withthe liquid food substance; and cooling said mixture.
 18. A methodaccording to claim 17, wherein the step of whipping includes propellinga first portion of the mixture in a first direction toward said outletend and propelling a second portion of the mixture in a second directionopposite said first direction.
 19. A method according to claim 17,wherein the step of mixing includes mixing nitrous oxide with the liquidfood substance in a ratio of at least one part nitrous oxide to one partliquid food substance.
 20. A method according to claim 17, wherein thestep of cooling includes cooling the mixture to about 9° F. in about 7-8minutes.
 21. A method according to claim 17, wherein the step or coolingincludes cooling the mixture down to at least 15° F.